Lamps are commonly supported, either in part or wholly, by the lamp leads and in particular, by a pin structure coupled to the leads. The mechanical stress put on the leads by repeated coupling and uncoupling the lamp can break down the lead seals, causing the lamp to fail. The mechanical stress on the leads may be particularly excessive in expensive lamps that are either rented, or otherwise moved from location to location for short term use. Studio lamps are an example of lights that are frequently moved, and are subjected to lead stress. The frequent coupling and uncoupling of the lamp leads can then result in premature lamp failure. One method to resist the lead stress is to form an insulating bridge between the leads. Unfortunately, for high wattage lamps, the leads become hot during service causing thermal stress between the leads and bridge. Disproportionate thermal expansion in the mechanical protection can cause thermal destruction of the lamp seal. There is then a need for a structure to strengthen the lamp leads and in particular the lamp leads of high wattage, pin base lamps, without weakening the existing seals, or transmitting thermal stress.
An examples of the prior art is shown in U.S. Pat. No. 2,252,476. U.S. Pat. No. 2,252,476 Wright shows a sealed beam lamp with a cap structure enclosing the seals and coupling the distal ends of the lamp leads. The cap provides a thermal expansion joint between the cap and reflector back.